Wednesday, 19 February 2014

Oxwich Marsh

This blog is a few day late due to heavy commitments.

Recent bad weather has restricted ringing to my garden which is slightly sheltered. Today was the first visit to Oxwich Marsh since the 19th January. It is a coastal site so the winds are always stronger than a few miles inland. Overnight there had been a heavy frost but temperatures stated to rise quickly as the sun tried to come out.
Out of the 37 birds caught we caught the normal Tits, Chaffinch, Dunnock and Robins, but the highlight of the day was the capture of 10 Reed Bunting, 4 of which were re-traps.

Reed Buntings can be a difficult bird to age. Many first year juveniles can moult all their Greater  Coverts and moult limit is difficult to see. Tail feather shape tends to be the main way to determine the birds age but some first year birds do moult all the tail feathers which makes it difficult to differentiate them from adult birds. The amount of wear of a juvenile bird that has retained its tail feathers compared to an adult can often be seen. However it is a Reed Bunting and they live in reed beds and the reed environment can be very abrasive on their feather so caution must be taken and if in doubt age it as a 4.

This male Reed Bunting clearly shows the breeding plumage is starting to develop.

We also caught 2 Greenfinch, both males.

Looking at the tail feathers you would be forgiven for thinking that the bird in the hand was an adult bird. This was my original thought until I started to look at the wing.

This wing gives you three clues that this bird in a juvenile.

1. The Alula is a dirty yellow colour which is indicative of a juvenile bird. The adult Alula would be a bright vibrant yellow.
2. The GC's look un-moulted with brownish/yellow fringing looking dull and lighter greyish colour tips.
3. It looks as if all the primaries are not moulted. Primaries 2- 5 which can be seen in the picture, are very pointed.

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